Can Sinus Blockage Cause Delayed Speech And Breathlessness?

Hi my child (2 yrs and 2 months) had cough and cold very frequently this winter. She was extremely good in her speech and could talk fluently. Two weeks earlier suddenly she started finding it difficult to utter words starting with a,u and could not complete the words. Example she will get stuck saying a.a a.a.a.a.a.a till she would be breathless and then leave it without uttering. Slowly she was getting stuck in other words also like b, k, p etc... Dr said its because of sinus blockage. She is given medicine to cure alergy and recommended nebuliser. She is a lot better now. Can say all words clearly now except a and u.. Can she ratio some benefit from this medicine.